A Brain Atlas of the Long Arm Octopus, Octopus minor

Abstract

Cephalopods have the most advanced nervous systems and intelligent behavior among all invertebrates. Their brains provide comparative insights for understanding the molecular and functional origins of the human brain. Although brain maps that contain information on the organization of each subregion are necessary for a study on the brain, no whole brain atlas for adult cephalopods has been constructed to date. Here, we obtained sagittal and coronal sections covering the entire brain of adult Octopus minor (Sasaki), which belongs to the genus with the most species in the class Cephalopoda and is commercially available in East Asia throughout the year. Sections were stained using Hematoxylin and Eosin (H&E) to visualize the cellular nuclei and subregions. H&E images of the serial sections were obtained at 30~70-µm intervals for the sagittal plain and at 40~80-µm intervals for the coronal plain. Setting the midline point of the posterior end as the fiducial point, we also established the distance coordinates of each image. We found that the brain had the typical brain structure of the Octopodiformes. A number of subregions were discriminated by a Hematoxylin-positive layer, the thickness and neuronal distribution pattern of which varied markedly depending upon the region. We identified more than 70 sub-regions based on delineations of representative H&E images. This is the first brain atlas, not only for an Octopodiformes species but also among adult cephalopods, and we anticipate that this atlas will provide a valuable resource for comparative neuroscience research.

Distribution of Cadherin in the Parahippocampal Area of Developing Domestic Chicken Embryos

“…Our results regarding the changes between different subregions indicate that Cdh2, Cdh8, Pcdh8 and Pcdh10 might have regionally homologous expression in chicken and mouse hippocampal formations. This is consistent with Cindrova-Davies' research [60] on the functionally conservation of yolk sac among human, mouse and chicken [61]. Similarly, the complicated brain has its own evolutionary mechanism and conserved genetic system.…”

Identification of neural progenitor cells and their progeny reveals long distance migration in the developing octopus brain

“…Synaptotagmin is a presynaptic calcium sensor necessary for neurotransmitter release, present in mature synapses and thus in differentiated, functional neurons (Poskanzer et al, 2003). In addition, we also visualized neuronal somata and neuropil using immunoreactivity against acetylated alpha-tubulin, as previously described for multiple cephalopod species (Figure 2, S2.3) (Jung et al, 2018;Kingston et al, 2015;Scaros et al, 2018;Shigeno et al, 2015;Shigeno & Yamamoto, 2002;Wollesen et al, 2009Wollesen et al, , 2012. In O. vulgaris, we observed expression of Ov-syt in the retina from Stage XI onwards.…”

Identification of neural progenitor cells and their progeny reveals long distance migration in the developing octopus brain

“…Synaptotagmin is a presynaptic calcium sensor necessary for neurotransmitter release, present in mature synapses and thus in differentiated, functional neurons ( Poskanzer et al, 2003 ). In addition, we also visualized neuronal somata and neuropil using immunoreactivity against acetylated alpha-tubulin, as previously described for multiple cephalopod species ( Figure 2H–U , Figure 2—figure supplement 3 ; Jung et al, 2018 ; Kingston et al, 2015 ; Scaros et al, 2018 ; Shigeno et al, 2015 ; Shigeno and Yamamoto, 2002 ; Wollesen et al, 2009 ; Wollesen et al, 2012 ). In O. vulgaris , we observed expression of Ov-syt in the retina from Stage XI onwards ( Figure 2H,I ).…”